As for the weight thing, I am carrying 300# on a 5'7" frame, have been overweight my entire adult life.
Gastric bypass seems kind of extreme for your weight. If it is the only way you can lose the weight then maybe it is the way to go, but I would work really hard at more conventional options first. Gastric bypass will still require that you learn to do what it takes to maintain a healthy weight eventually or else you will ultimately wind up putting the weight back on some years down the road. At least that is what happened to am acquaintance of mine who had bypass and still ate all he wanted.
Do you have no chance of a leave of absence? I did the TA at age 57 and told
my employer I was going to do it and asked
if I would have a job when I got back. They said yes and I found that it actually helped rather than hurt my career. I guess that they missed me and figured out that I was more useful than they realized and that no one else that was available could do my job as well. Also I was pretty sure that another department of my same employer, that I worked for before, would hire me if they didn't hold my job.
FWIW, I have found a healthy weight easier to maintain now that I am retired. I find it easier to exercise every day and I tend to eat a lot less during the day than I did at work. Currently I trail run 4-8 miles almost every day and eat mostly what I feel like and still maintain a weight that I am happy with. I had been successfully calorie counting using Livestrong.com'a myplate for a while before I retired, but after retirement I found it unnecessary. Work was the worst for me. Too many donuts and meeting leftovers set out. Too much stress. Too much temptation to go get a coffee and a snack to get away from my desk.